Charles e



(No Model.)

0. E. CARPENTER. ELECTRIC SOLDERING IRON.

No. 433,671. Patented Aug. 5, 1890.

5 QR NEWYN Q A w UNITED STATES PATENT Orricn.

CHARLES E. CARPENTER, OF MINNEAPOLIS, MINNESOTA, ASSIGNOR TO THECARPENTER-NEVENS ELECTRO-HEATING COMPANY, OF SAME PLACE.

ELECTRIC SOLDERlNG-IRON.

SPECIFICATION forming part of Letters Patent No. 433,671, dated August5, 1890.

Application filed May 10, 1890. Serial No. 351,268. (No model.)

To all whom it may concern:

Be it known that 1, CHARLES E. CARPENTER, a citizen of the UnitedStates, residing in the city of Minneapolis, in the county of Hennepinand State of Minnesota, have invented certain new and usefulImprovements in Electric Soldering-Irons, of which the following is aspecification.

This invention relates to improvements in re electric soldering-irons,in which heretofore the resistance or electrical conductor has beenwound or disposed about a cylinder or body of copper provided with atapering head, to which the heat generated in the resistance is isconducted through the medium of the body, the resistance or body beingcovered with some heat-insulating material, leaving onlya tapering heador point of the iron exposed. It is obvious and well understood thatwith such a construction there is considerable waste of energy orcurrent, because of the great radiating or heating surface of the body,which must first be heated to a high degree before the head or point ofthe iron, which can alone be utilized in practice,is heated to asufficient degree. Besides which, practice has demonstrated that thespace is too small to provide sufficient heat-insulation between theoutside covering or casing and the body or cylo inder portion of theiron, and hence the cars ing will be heated to a temperaturesufficiently high to be not only extremely objectionable, but wastefulof much of the energy supplied to the iron.

5 The prime object of my invention is to heat and confine the heat onlyto that portion of the iron which is employed in practice-that is, thehead or point thereof whereby the compactness, simplicity, andeffectiveness of the iron is promoted to the maximum degree, while theiron is rendered much lighter and therefore easier of manipulation andmore economical in use.

Another object is to dispense with the cylindrical body portion of theiron and the accompanying heat insulation and the easing therefor, andat the same time have the handle of the iron so connected with theheated portion thereof as to avoid the ob eetionable heating of thesame.

A further object is to have the iron of such construction that anydesired degree of pressure may be employed in binding the elementstogether, whereby the effect of the heat These objects are attained bythe devices illustrated in the accompanying drawings, in which Figure 1represents a central longitudinal section through a soldering-ironembodying my invention; Fig. 2, a transverse vertical 0 5 sectionthereof on the line 2 2 of Fig. 1; Fig.

3, a detail longitudinal section through the iron, showing a modifiedconstruction thereof; and Fig. 4, a detail side elevation of a modifiedform of core. 7

Similar letters of reference indicate the same parts in the severalfigures of the drawings.

lhis iron, so far as relates to the general disposition of its elements-that is to say, the resistance or electrical conductor and theelectrical insulations thereofis somewhat similar to that shown in myapplication for Letters Patent, Serial N 0. 4,354, filed March 18, 1890,upon which this invention is more es- 8o pecially designed to be animprovement, but is wholly different in its general features ofconstruction.

Referring now by letter to the accompanying drawings, A indicates a corehaving the contour of a frustum of a cone, the conical surface of whichis covered with a layer of electrical insulating material B, of uniformthickness and of a character that will endure high temperature and is afair conductor of heat-such as asbestus paperupon which is tightly woundin a spiral coil the resistance or. electrical conductor C, consistingpreferably of a line metallic wire of highly-refract ory character,beginning at one end of the cone and terminating at the other, theterminal D near the apex of the cone preferably being insulated, andbrought back througha hole or passage in the core, and then united withone of the line-Wires E, lying in the 0011- I00 tral passage, throughthe handle of the iron, the other line-wire F also leading through thehandle and being connected "with the opposite terminal of the resistanceat or near the base of the cone.

The outer shell or body G, consisting preferably of copper and having aconical exterior surface similar in shape to that of an ordinarysoldering-iron, is employed for receiving the core an d the electricalresistance wound thereon, to which end it is provided with a taperingcavity corresponding to the taper of the core A, which cavity is firstlined with a layer of an electrical insulating material H, similar tothat already described for. the core, after which the core, with itscovering of insulation and resistance-wire, is inserted in position inthe cavity and forc edfirmly against the walls thereof by means of ascrew I, passing axiallythrough the core and entering a screw-threadedsocket in the tip of the shell or body of the iron, thereby firmlybinding the elements together under any desired pressure and securingthem in position against displacement due to jarring or blows upon theiron in its practical use, or to the possible shrinkage of theelectrical insulations between the resistance and the body and core ofthe iron as a result of the great heat to which they are subjected.

This iron as a whole is secured to a handle J, of any suitable form ormaterial for convenience of manipulation, by means of a tube K, having ascrew-thread connection at one end with the ferrule L of the handle andat its opposite end with a cap M, secured to the core of the iron bymeans of the screws N, between which cap and the iron proper is inserteda layer of asbestus or some other heat insulating material 0, forpreventing to the greatest possible degree the conduction of the heatfrom the iron to the handle, the cap be ing preferably recessed. on theinner face thereof, so as to provide an air-space for promoting theheat-insulation and at the same time furnish a passage for the disposalof the resistance-wires.

From the foregoing description it will be readily seen that the heatevolved from the resistance or electrical conductor is utilized to themaximum degree, for with no cylindrical body portion to which the heatis first imparted, as has heretofore been the case, only the part of theiron which itis practically desired to heattl1at is, the head or pointthereofwill now be heated, and by the employment of the core the pointor head of theiron is rendered practically solid and will retain in themaximum degree the heat imparted thereto, andlwhich has heretofore beendissipated through the heat-insulations and casing of the iron body.

If desired, to insure the retention of the resistance in fixed relationto the core the whole may be provided in the conical surface thereofwith a spiral groove, as illustrated in Figs. 3 and 4, into which thewire and electrical insulation will be sunk, and

the convolutions of the wire thus retained in position against slippingupon the cone, this groove, while not absolutely essential to thesuccessful operation of my invention, at the same time being anadvantageous feature of construction.

Other minor changes in details of construction may obviously be employedwithout departing from the spirit of my invention, so long as theresistance or electrical conductor is confined within, so as to directlyheat the point or head of the iron as distinguished from the indirectheating thereof, heretofore accomplished through the medium of thecylindrical body portion of the iron to the rear of the head.

Having described my invention, what I claim, and desire to secure byLetters Patent, 1s

1. In an electric soldering-iron, the combination, with the hollow bodyand the tapering core fitting within said body, of the resistancedisposed about the core, and electrical insulations interposed betweensaid resistance and the core and body, substantially as described.

2. In an electric soldering-iron, the combination, with the hollow bodyand the tapering core fitting within said body, of the resistancedisposed about said core, electrical insulations interposed between saidresist-' ance and the core and body, and means for binding said elementstogether under pressure, substantially as described.

3. In an electric soldering-iron, the combination, with the hollow body,the tapering core fitting within said body, the resistance disposedabout said core, electrical insulations interposedbetween saidresistance and the core and body, and means for binding said partstogether, of the handle attached to said core and the heat-insulationinterposed between said handle and the core and body, substantially asdescribed.

4. In an electric soldering-iron, the combination, with the hollowconical body and the tapering core fitting within said body, of theresistance disposed about said core, electrical insulations interposedbetween said resistance and the core and body, anda screw passingaxially through the core and engaging the body, so as to bind the saidmembers firmly together under pressure, substantially as described.

5. In an electric soldering-iron, the combination, with the hollow body,of a tapering core having a spiral groove in the conical surface thereofand fitting within said body, of the resistance and electric insulationsinterposed between said resistance and the core and body, substantiallyas described.

CHARLES E. CARPENTER.

Witnesses:

A. C. SANDERS, R. V. CHANY.

